http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58472
--- Comment #9 from vincenzo Innocente <vincenzo.innocente at cern dot ch> --- w/o opening another bug report c++ -O2 -S omp4red.cc -fopenmp -Wall omp4red.cc: In function ‘float sumO1()’: omp4red.cc:6:9: warning: ‘simduid.0’ is used uninitialized in this function [-Wuninitialized] #pragma omp simd reduction(+:s) ^